/*****************************************************************************

Copyright (c) 1994, 2010, Innobase Oy. All Rights Reserved.
Copyright (c) 2009, Sun Microsystems, Inc.

Portions of this file contain modifications contributed and copyrighted by
Sun Microsystems, Inc. Those modifications are gratefully acknowledged and
are described briefly in the InnoDB documentation. The contributions by
Sun Microsystems are incorporated with their permission, and subject to the
conditions contained in the file COPYING.Sun_Microsystems.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 
51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

*****************************************************************************/

/******************************************************************//**
@file include/ut0ut.h
Various utilities

Created 1/20/1994 Heikki Tuuri
***********************************************************************/

#ifndef ut0ut_h
#define ut0ut_h

#include "univ.i"

#include "db0err.h"

#ifndef UNIV_HOTBACKUP
# include "os0sync.h" /* for HAVE_ATOMIC_BUILTINS */
#endif /* UNIV_HOTBACKUP */

#include <time.h>
#ifndef MYSQL_SERVER
#include <ctype.h>
#endif

/** Index name prefix in fast index creation */
#define	TEMP_INDEX_PREFIX	'\377'
/** Index name prefix in fast index creation, as a string constant */
#define TEMP_INDEX_PREFIX_STR	"\377"

/** Time stamp */
typedef time_t	ib_time_t;

#ifndef UNIV_HOTBACKUP
#if defined(HAVE_PAUSE_INSTRUCTION)
   /* According to the gcc info page, asm volatile means that the
   instruction has important side-effects and must not be removed.
   Also asm volatile may trigger a memory barrier (spilling all registers
   to memory). */
#  define UT_RELAX_CPU() __asm__ __volatile__ ("pause")
#elif defined(HAVE_FAKE_PAUSE_INSTRUCTION)
#  define UT_RELAX_CPU() __asm__ __volatile__ ("rep; nop")
#elif defined(HAVE_ATOMIC_BUILTINS)
#  define UT_RELAX_CPU() do { \
     volatile lint	volatile_var; \
     os_compare_and_swap_lint(&volatile_var, 0, 1); \
   } while (0)
#elif defined(HAVE_WINDOWS_ATOMICS)
   /* In the Win32 API, the x86 PAUSE instruction is executed by calling
   the YieldProcessor macro defined in WinNT.h. It is a CPU architecture-
   independent way by using YieldProcessor. */
#  define UT_RELAX_CPU() YieldProcessor()
#else
#  define UT_RELAX_CPU() ((void)0) /* avoid warning for an empty statement */
#endif

/*********************************************************************//**
Delays execution for at most max_wait_us microseconds or returns earlier
if cond becomes true.
@param cond		in: condition to wait for; evaluated every 2 ms
@param max_wait_us	in: maximum delay to wait, in microseconds */
#define UT_WAIT_FOR(cond, max_wait_us)				\
do {								\
	ullint	start_us;					\
	start_us = ut_time_us(NULL);				\
	while (!(cond) 						\
	       && ut_time_us(NULL) - start_us < (max_wait_us)) {\
								\
		os_thread_sleep(2000 /* 2 ms */);		\
	}							\
} while (0)
#endif /* !UNIV_HOTBACKUP */

/********************************************************//**
Gets the high 32 bits in a ulint. That is makes a shift >> 32,
but since there seem to be compiler bugs in both gcc and Visual C++,
we do this by a special conversion.
@return	a >> 32 */
UNIV_INTERN
ulint
ut_get_high32(
/*==========*/
	ulint	a);	/*!< in: ulint */
/******************************************************//**
Calculates the minimum of two ulints.
@return	minimum */
UNIV_INLINE
ulint
ut_min(
/*===*/
	ulint	 n1,	/*!< in: first number */
	ulint	 n2);	/*!< in: second number */
/******************************************************//**
Calculates the maximum of two ulints.
@return	maximum */
UNIV_INLINE
ulint
ut_max(
/*===*/
	ulint	 n1,	/*!< in: first number */
	ulint	 n2);	/*!< in: second number */
/****************************************************************//**
Calculates minimum of two ulint-pairs. */
UNIV_INLINE
void
ut_pair_min(
/*========*/
	ulint*	a,	/*!< out: more significant part of minimum */
	ulint*	b,	/*!< out: less significant part of minimum */
	ulint	a1,	/*!< in: more significant part of first pair */
	ulint	b1,	/*!< in: less significant part of first pair */
	ulint	a2,	/*!< in: more significant part of second pair */
	ulint	b2);	/*!< in: less significant part of second pair */
/******************************************************//**
Compares two ulints.
@return	1 if a > b, 0 if a == b, -1 if a < b */
UNIV_INLINE
int
ut_ulint_cmp(
/*=========*/
	ulint	a,	/*!< in: ulint */
	ulint	b);	/*!< in: ulint */
/*******************************************************//**
Compares two pairs of ulints.
@return	-1 if a < b, 0 if a == b, 1 if a > b */
UNIV_INLINE
int
ut_pair_cmp(
/*========*/
	ulint	a1,	/*!< in: more significant part of first pair */
	ulint	a2,	/*!< in: less significant part of first pair */
	ulint	b1,	/*!< in: more significant part of second pair */
	ulint	b2);	/*!< in: less significant part of second pair */
/*************************************************************//**
Determines if a number is zero or a power of two.
@param n	in: number
@return		nonzero if n is zero or a power of two; zero otherwise */
#define ut_is_2pow(n) UNIV_LIKELY(!((n) & ((n) - 1)))
/*************************************************************//**
Calculates fast the remainder of n/m when m is a power of two.
@param n	in: numerator
@param m	in: denominator, must be a power of two
@return		the remainder of n/m */
#define ut_2pow_remainder(n, m) ((n) & ((m) - 1))
/*************************************************************//**
Calculates the biggest multiple of m that is not bigger than n
when m is a power of two.  In other words, rounds n down to m * k.
@param n	in: number to round down
@param m	in: alignment, must be a power of two
@return		n rounded down to the biggest possible integer multiple of m */
#define ut_2pow_round(n, m) ((n) & ~((m) - 1))
/** Align a number down to a multiple of a power of two.
@param n	in: number to round down
@param m	in: alignment, must be a power of two
@return		n rounded down to the biggest possible integer multiple of m */
#define ut_calc_align_down(n, m) ut_2pow_round(n, m)
/********************************************************//**
Calculates the smallest multiple of m that is not smaller than n
when m is a power of two.  In other words, rounds n up to m * k.
@param n	in: number to round up
@param m	in: alignment, must be a power of two
@return		n rounded up to the smallest possible integer multiple of m */
#define ut_calc_align(n, m) (((n) + ((m) - 1)) & ~((m) - 1))
/*************************************************************//**
Calculates fast the 2-logarithm of a number, rounded upward to an
integer.
@return	logarithm in the base 2, rounded upward */
UNIV_INLINE
ulint
ut_2_log(
/*=====*/
	ulint	n);	/*!< in: number */
/*************************************************************//**
Calculates 2 to power n.
@return	2 to power n */
UNIV_INLINE
ulint
ut_2_exp(
/*=====*/
	ulint	n);	/*!< in: number */
/*************************************************************//**
Calculates fast the number rounded up to the nearest power of 2.
@return	first power of 2 which is >= n */
UNIV_INTERN
ulint
ut_2_power_up(
/*==========*/
	ulint	n)	/*!< in: number != 0 */
	__attribute__((const));

/** Determine how many bytes (groups of 8 bits) are needed to
store the given number of bits.
@param b	in: bits
@return		number of bytes (octets) needed to represent b */
#define UT_BITS_IN_BYTES(b) (((b) + 7) / 8)

/**********************************************************//**
Returns system time. We do not specify the format of the time returned:
the only way to manipulate it is to use the function ut_difftime.
@return	system time */
UNIV_INTERN
ib_time_t
ut_time(void);
/*=========*/
#ifndef UNIV_HOTBACKUP
/**********************************************************//**
Returns system time.
Upon successful completion, the value 0 is returned; otherwise the
value -1 is returned and the global variable errno is set to indicate the
error.
@return	0 on success, -1 otherwise */
UNIV_INTERN
int
ut_usectime(
/*========*/
	ulint*	sec,	/*!< out: seconds since the Epoch */
	ulint*	ms);	/*!< out: microseconds since the Epoch+*sec */

/**********************************************************//**
Returns the number of microseconds since epoch. Similar to
time(3), the return value is also stored in *tloc, provided
that tloc is non-NULL.
@return	us since epoch */
UNIV_INTERN
ullint
ut_time_us(
/*=======*/
	ullint*	tloc);	/*!< out: us since epoch, if non-NULL */
/**********************************************************//**
Returns the number of milliseconds since some epoch.  The
value may wrap around.  It should only be used for heuristic
purposes.
@return	ms since epoch */
UNIV_INTERN
ulint
ut_time_ms(void);
/*============*/
#endif /* !UNIV_HOTBACKUP */

/**********************************************************//**
Returns the difference of two times in seconds.
@return	time2 - time1 expressed in seconds */
UNIV_INTERN
double
ut_difftime(
/*========*/
	ib_time_t	time2,	/*!< in: time */
	ib_time_t	time1);	/*!< in: time */
/**********************************************************//**
Prints a timestamp to a file. */
UNIV_INTERN
void
ut_print_timestamp(
/*===============*/
	FILE*	file)	/*!< in: file where to print */
	UNIV_COLD __attribute__((nonnull));
/**********************************************************//**
Sprintfs a timestamp to a buffer, 13..14 chars plus terminating NUL. */
UNIV_INTERN
void
ut_sprintf_timestamp(
/*=================*/
	char*	buf); /*!< in: buffer where to sprintf */
#ifdef UNIV_HOTBACKUP
/**********************************************************//**
Sprintfs a timestamp to a buffer with no spaces and with ':' characters
replaced by '_'. */
UNIV_INTERN
void
ut_sprintf_timestamp_without_extra_chars(
/*=====================================*/
	char*	buf); /*!< in: buffer where to sprintf */
/**********************************************************//**
Returns current year, month, day. */
UNIV_INTERN
void
ut_get_year_month_day(
/*==================*/
	ulint*	year,	/*!< out: current year */
	ulint*	month,	/*!< out: month */
	ulint*	day);	/*!< out: day */
#else /* UNIV_HOTBACKUP */
/*************************************************************//**
Runs an idle loop on CPU. The argument gives the desired delay
in microseconds on 100 MHz Pentium + Visual C++.
@return	dummy value */
UNIV_INTERN
ulint
ut_delay(
/*=====*/
	ulint	delay);	/*!< in: delay in microseconds on 100 MHz Pentium */
#endif /* UNIV_HOTBACKUP */
/*************************************************************//**
Prints the contents of a memory buffer in hex and ascii. */
UNIV_INTERN
void
ut_print_buf(
/*=========*/
	FILE*		file,	/*!< in: file where to print */
	const void*	buf,	/*!< in: memory buffer */
	ulint		len);	/*!< in: length of the buffer */

/**********************************************************************//**
Outputs a NUL-terminated file name, quoted with apostrophes. */
UNIV_INTERN
void
ut_print_filename(
/*==============*/
	FILE*		f,	/*!< in: output stream */
	const char*	name);	/*!< in: name to print */

#ifndef UNIV_HOTBACKUP
/* Forward declaration of transaction handle */
struct trx_struct;

/**********************************************************************//**
Outputs a fixed-length string, quoted as an SQL identifier.
If the string contains a slash '/', the string will be
output as two identifiers separated by a period (.),
as in SQL database_name.identifier. */
UNIV_INTERN
void
ut_print_name(
/*==========*/
	FILE*		f,	/*!< in: output stream */
	struct trx_struct*trx,	/*!< in: transaction */
	ibool		table_id,/*!< in: TRUE=print a table name,
				FALSE=print other identifier */
	const char*	name);	/*!< in: name to print */

/**********************************************************************//**
Outputs a fixed-length string, quoted as an SQL identifier.
If the string contains a slash '/', the string will be
output as two identifiers separated by a period (.),
as in SQL database_name.identifier. */
UNIV_INTERN
void
ut_print_namel(
/*===========*/
	FILE*		f,	/*!< in: output stream */
	struct trx_struct*trx,	/*!< in: transaction (NULL=no quotes) */
	ibool		table_id,/*!< in: TRUE=print a table name,
				FALSE=print other identifier */
	const char*	name,	/*!< in: name to print */
	ulint		namelen);/*!< in: length of name */

/**********************************************************************//**
Catenate files. */
UNIV_INTERN
void
ut_copy_file(
/*=========*/
	FILE*	dest,	/*!< in: output file */
	FILE*	src);	/*!< in: input file to be appended to output */
#endif /* !UNIV_HOTBACKUP */

#ifdef __WIN__
/**********************************************************************//**
A substitute for snprintf(3), formatted output conversion into
a limited buffer.
@return number of characters that would have been printed if the size
were unlimited, not including the terminating '\0'. */
UNIV_INTERN
int
ut_snprintf(
/*========*/
	char*		str,	/*!< out: string */
	size_t		size,	/*!< in: str size */
	const char*	fmt,	/*!< in: format */
	...);			/*!< in: format values */
#else
/**********************************************************************//**
A wrapper for snprintf(3), formatted output conversion into
a limited buffer. */
# define ut_snprintf	snprintf
#endif /* __WIN__ */

/*************************************************************//**
Convert an error number to a human readable text message. The
returned string is static and should not be freed or modified.
@return	string, describing the error */
UNIV_INTERN
const char*
ut_strerr(
/*======*/
	enum db_err	num);	/*!< in: error number */

#ifndef UNIV_NONINL
#include "ut0ut.ic"
#endif

#endif

